Yarn tensioning device for knitting machines



March 22, 1966 B, FRIED 3,241,339

YARN TENSIONING DEVICE FOR KNITTING MACHINES Filed Oct. 8, 1963 IN VENTOR.

BENJAMIN FRIED F|G.|.

ATTOR United States Patent 3,241,339 YARN TENSTGNTNG DEVICE FQR KNITTING MACHINES Ben amin Fried, 835 Lenox Ave., Miami Beach, Fla. Fiied 0st. 8, 1963, Ser. No. 314,668 5 Claims. ((11. 66-146) This invention relates to yarn tensioning devices and more particularly to devices for tensioning yarns in a knitting machine.

In a circular knitting machine yarn is often stored on supply cones or bobbins which are mounted on a rack or framework above that part of the machine where the knitting takes place. The yarns from the cones are guided downward into position to be picked up by the needles of the machine. The moving needles must pull the yarns from the supply cones, since there is no provision for positively feeding the yarns from the cones to the needles. Thus, the yarn is pulled under tension by the needle moving at high speeds up and down thus causing a tearing action when pulling yarn directly from the supply cone into the fabric in order toknit vertical stripes, this tension often resulting in yarn breakage or uneven vertical stitches. Also, tension may vary from one yarn to the next due to uneven winding tension of supply cones. This also results in uneven vertical stitches. With this in mind, one of the objects of this invention is to provide a novel and improved yarn tensioning system.

Another object of this invention is to provide a device for equalizing tensions in the different yarns used in a knitting machine for knitting vertical stripes.

A further object of this invention is to provide a system for providing a predetermined amount of slack in a yarn being fed to a knitting machine needle so that the yarn is subjected to a constant, lower-than-usual, tension each time the needle pulls the yarn to knit a vertical stripe. One embodiment of the present invention contemplates a yarn tensioning device for use in a circular knitting machine having a rotating rack or framework mounted above the needle cylinder for holding a number of yarn supply cones. The yarns from the supply cones are fed downward along the framework into positions to be picked up by the needles as the framework rotates, the yarn paths or threadlines rotating with the framework. To insure that each yarn is pulled into the fabric under the same tension in order to make uniform vertical stripes, the present invention provides a predetermined amount of slack in each yarn just prior to the moment when a needle pulls the yarn into the fabric. This is accomplished in one embodiment of the invention by securing a pair of spaced rings to the rotating framework and by feeding the yarn through a pair of aligned apertures in the rings. A plurality of stationary spaced fingers secured to the machine base are positioned so that the free ends thereof extends into the space between the rings so as to engage the yarn at this point. Each finger is positioned at an angle so that the yarn is deflected from its normal vertical path (between the rings) as it slides over the free end of the finger. This deflection of the yarn from a straight path to a curved path pulls a small amount of yarn olf the supply bobbin so that, after the yarn clears the finger, there is a predetermined amount of slack in the yarn. This slack is pulled out of yarn when the needle engages the yarn immediately after the yarn clears the finger.

Other objects and advantages of the invention will become apparent when the following detailed description is read in conjuction with the appended drawing, in which:

FIGURE 1 is a side view of a. circular knitting machine on which the device of the present invention has been mounted,

FIGURE 2 is an enlarged fragmentary perspective view showing one of the fingers deflecting one of the yarns as the yarn moves past the finger, and

FIGURE 3 is the view of FIGURE 2 after the yarn has cleared the finger, showing the slack in the yarn.

Referring now in detail to the drawing, a knitting machine 11 is shown having a rotating framework 12 upon which is mounted a plurality of yarn supply cones 13. This machine is disclosed in greater deatin in US. Patent No. 3,018,645, issued on January 30, 1962, to Benjamin Fried.

A base 16 of the machine 11 supports a plurality of stationary rods 17 which extend vertically upward outside the revolving framework 12. The framework is driven by a motor 18 mounted on the base 16 and acting through a gear 21 meshed with a ring gear 22 secured to the framework 12. Yarns 25 are fed downward through guides 26 on the framework 12 and are picked up by needles (not shown in detail), the needles producing a vertical stripe in a fabric 27 which is taken up on a roll 28 below the machine. It can readily be seen that the paths of the yarns 25, or the threadlines, are carried laterally with the framework 12 along circular paths. The structure and operation described thus far is described in detail in the above-mentioned patent.

The device of the present invention includes a pair of spaced, superposed rings 31 and 32 (shown in section in FIGURE 1) which are attached to brackets 33 secured to the rotating framework 12. The rings 31 and 32 are provided with vertically-aligned eyelet guides 35 and 36, respectively, through which the yarn 25 passes vertically along a normally straight path between the rings.

Rods attached to the base 16 support an outer ring 41 secured to the rods 40. The rods 40 extend through holes in the ring 41 and have the upper ends thereof threaded for receiving nuts 42 which hold fingers 45, the ends of the fingers 45 being looped to fit over the rods 40. The fingers 45, which may be made from heavy wire, extend inwardly from the outer ring 41 into the space between the inner rings 31 and 32 so. that each yarn 25 is engaged by the free end of each of the fingers. The fingers 45 are curved and positioned at angles as shown so that the yarns will more easily slip over the free ends of the fingers. i

In operation of the apparatus, the framework 12 rotates continuously to rotate the inner rings 31 and 32 through which the yarns 25 pass. Each yarn passes to the needles and is periodically engaged by the needles. The finger 45 is positioned to engage the yarn 25 just prior to engagement of the yarn with a needle, the yarn clearing the finger just before this engagement.

The finger 45 extends inwardly to a point spaced inside the circle defined by the eyelet guides 35 and 36 and the yarn path therebetween. The moving yarn 25 engages the curved and angled finger 45 and slides therealong. Since the finger 45 extends to a position radially inward from the threadline, the yarn 25 is deflected from its normal straight path between the eyelet guides 35 and 36, as shown in FIGURE 2. The deflection of the yarn from its normal straight path pulls a small amount of yarn off the supply cone 13 so that, after the yarn 25 slides over and clears the finger 45, a small amount of slack is left in the yarn, as best shown in FIGURE 3.

Immediately after the yarn 25 clears the finger 45, it is engaged by one of the needles and pulled into the fabric. The slack in the yarn insures that the needle will pull the yarn under practically no tension. This in turn insures perfectly formed stitches and eliminates the possibility of yarn breakage. The fingers 45 are so positioned that each yarn is provided with slack prior to the stitching of that yarn.

In operation, the framework 12 is rotated in the manner described above to sweep the yarn paths or threadlines laterally through circular paths. Each yarn is periodically engaged and deflected from its normal circular path by the fingers 45. Since the yarn 25 is attached to the fabric under construction, this deflection pulls a small amount of yarn from the supply cone 137 When the yarn 25 clears the finger 45 there remains in the yarn a small amount of slack. This slack is pulled out when one of the needles engages and pulls the yarn.

In a machine having, for example, 64 yarn feeds there should be 64 fingers 45, each being positioned to provide yarn slack just prior to the formation of the vertical stripe stitch. Alternately, 32 fingers 45 may be used, each extending radially inward a sulficient distance to provide twice as much yarn slack as necessary for the single stitch. In this case, two stitches are taken in the yarn subsequent to each engagement of the yarn with a finger 45.

This apparatus insures that each yarn will be pulled into the fabric at exactly the same tension, i.e., practically no tension. Thus, all stitches are very uniform. In addition, the yarn is more gently handled and there is no possibility of breaking a yarn.

It is to be understood that the embodiment disclosed herein is merely illustrative and that this embodiment can be altered or amended and that numerous other embodiments can be contemplated without departing from the spirit and scope of the invention.

What is claimed is:

1. In a fabric producing machine having a laterallymoving yarn supply path, a pair of spaced yarn guides secured to the machine for movement with said yarn path, said guides being adapted to direct a yarn along a substantially straight path therebetween, and a stationary deflecting member positioned to engage the yarn at a point between the guides and temporarily deflect the yarn from said straight path as the yarn moves past said member.

2. In a fabric producing machine having a laterallymoving threadline, a pair of spaced guides mounted on the machine for longitudinally guiding and laterally moving a yarn moving longitudinally along said threadline, and a stationary finger positioned to be engaged by the yarn as the threadline is moved therepast, said finger being mounted on one side of the threadline and having a free end extending to a position on the other side of said threadline, said finger being positioned at an angle so that the yarn engages and slides over the finger toward and over the free end thereof.

3. In a circular knitting machine having base suporting a rotating yarn supply framework wherein yarns are fed from cones on the framework downward to needles on the base, a yarn tensioning device, comprising a pair of spaced yarn guides secured to the framework for rotation therewith, said guides having therein vertically aligned apertures for receiving yarns, and a stationary element secured to the base and extending between the guides to a position radially inward of the yarn guides so as to engage the moving yarn and temporarily displace the yarn path between said guides.

4. In a circular knitting machine having a base supporting a rotating yarn supply framework wherein yarns are fed from cones on the framework downward along threadlines to needles on the base, a yarn tensioning device comprising a pair of spaced rings secured to the framework for rotation therewith, said rings having therein associated pair of yarn guiding apertures so that each yarn normally follows a predetermined path from one ring to the other, and a plurality of lingers mounted on the base and having free ends extending between the rings to intercept said yarn paths and displace the yarns from said paths and thereby provide a predetermined amount of slack in said yarns.

5. In a circular knitting machine having a base supporting a rotating yarn supply framework wherein yarns are fed from cones on the framework downward along threadlines to needles on the base, a yarn tensioning device comprising a pair of spaced. rings secured to the framework one above the other for rotation with the framework, said rings having therein pairs of vertically aligned apertures for receiving and guiding the yarns along normally straight threadlines between the rings, and a plurality of fingers mounted on the base and having free ends extending inwardly to positions between the rings for engaging and deflecting said threadlines to displace the yarns from said threadlines, said fingers being positioned so that each yarn engages and clears one of the fingers just prior to engagement of said yarn with one of the needles.

References Cited by the Examiner UNITED STATES PATENTS 2,038,722 4/1936 Dreyfus et al. 226--1l3 2,952,393 9/1960 Newton 66-132 X 3,018,645 1/1962 Fried 66-125 3,090,215 5/1963 Rosen 66l32 3,124,947 3/1964 Farmer 66-132 3,147,604 9/1964 Ziemba 66--146 FOREIGN PATENTS 1,913 8/1913 Great Britain.

DONALD W. PARKER, Primary Examiner. 

1. IN A FABRIC PRODUCING MACHINE HAVING A LATERALLYMOVING YARN SUPPLY PATH, A PAIR OF SPACED YARN GUIDES SECURED TO THE MACHINE FOR MOVEMENT WITH SAID YARN PATH, SAID GUIDES BEING ADAPTED TO DIRECT A YARN ALONG A SUBSTANTIALLY STRAIGHT THEREBETWEEN, AND A STATIONARY DEFLECTING MEMBER POSITIONED TO ENGAGE THE YARN AT A POINT BETWEEN THE GUIDES AND TEMPORARILY DEFLECT THE YARN FROM SAID STRAIGHT PATH AS THE YARN MOVES PAST SAID MEMBER. 